What is VoIP Cluster?

In this article you can read about an advanced telecommunication system, the VoIP cluster, and about why this system is important for a company's life. Those companies which intend to have international, even intercontinental relations should read this page carefully.

VoIP, or Voice over Internet Protocol is the technology used in every kind of Internet-based communication: every time a user initiates a message or a call through the Internet, the VoIP protocol manages the transmission of the data packets.

A VoIP cluster is a set of IP PBXs (Internet Protocol Public Branch Exchanges or Session Initiation Protocol (SIP) servers) that are connected to each other. These servers individually are the centres of a unique communication system, but by the connection of them, a greater system can be created. Of course, these servers can be connected through the Internet, what means that you and your company can have an access to different servers from all around the world.

VoIP Cluster Types

There are two types of VoIP clusters: there is one where the PBXs are connected to be one "big" server, and the other one where all the PBXs remain what they were designed to be, but they get connected. Let us see how the different types are used:

  • when the servers are connected into a great system, the capacity of this centre will be extremely high and all the features of the PBXs will be available. On the other hand, these PBXs can help and take each other's job, what means that the reliability of such a system is much greater than the single one.

    Since these servers work and behave as one server, the distribution of the extensions will be the same as in the case of only one PBX: all the SIP clients must have a unique extension number.

    The advantage of this solution is that it does not matter which PBX the extensions are connected to, and the extension numbers are easy to manage and to reach.

    Figure 1 represents a model system that uses this cluster:

    • PBX "A", PBX "B" and PBX "C" are connected into one system with SIP connections.
    • Since they are recognised by the extensions as one PBX, all the extensions can be numbered in order, without taking into consideration which PBX they belong to.
    • So Extension 11 and Extension 12 belongs to the same great system, it does not matter that Extension 11 is connected to PBX "A" and Extension 12 is connected to PBX "B".
    • The same is true in the case of Extension 13 and Extension 14.


    pbxs are connected into one great system and their extensions
    Figure 1 - The PBXs are connected into one great system and their extensions